1. Field of the Invention
This invention relates to an air purifier to remove at least some impurities from circulating air and in particular, although not necessarily solely, a freestanding electrically powered air purifier for domestic use.
2. Description of the Prior Art
Domestic air purifiers have become increasingly popular in recent times. The popularity is at least partially motivated by the decreasing quality of air in urban areas and also the greater appreciation of the adverse effects on health from such poor air quality.
Although various air purifiers are used in industry to at least partially clean exhaust gases, such industrial installations are generally not suitable for domestic use. The size of the installations and failure to be a single independent apparatus are problems. Also, the majority of the methods used are not suitable for miniaturisation and independent operation as a domestic appliance.
Amongst domestic air purifiers, one popular method uses a physical filter such as paper, carbon or a similar physical filter. However, such filters cause on-going problems in cleaning and/or replacing filter cartridges. Also, to be a factor against most airborne impurities, a relatively fine filter must be used. The filter itself with such small apertures creates considerable resistance to airflow through the apparatus. This resistance requires an increased motor size to provide sufficient airflow. The increase in motor size itself causes an increase in the initial cost of the appliance itself. It would also be understood that the increased motor size causes ongoing increased costs in the power usage as well as generally greater noise from such systems.
A further air purifying method used in domestic appliances comprises appliances relies on electrostatic attraction to perform the filtering or purification. In such appliances, air is passed over a plurality of charged panels that seek to attract the impurities through the opposition in electrostatic charge. This requires panels having a relatively large surface area for the passing air stream. Such electrostatic based appliances require the panels to be regularly removed, cleaned and replaced. The performance of such appliances drops sharply if the panels are not properly and regularly cleaned as the accumulation of charge across the panel neglects its effect. Furthermore, such appliances will only work on electrically charged particles and inert particulate materials will not be kept.
An object of the present invention is to provide a new and improved air purifier that will overcome some of the difficulties in the prior art or at least provide the public with a viable alternative.
According to a first aspect of the invention, the air purifier comprises a plurality of tubes through which room air is drawn, a fluid reservoir, fluid conduits leading from the fluid reservoir to nozzles communicating with each of the plurality of tubes and means for pumping the fluid. Room air is propelled through the plurality of tubes where the air comes in contact with and preferably mixes with the fluid spraying from the nozzles. This intimate contact between the air and the fluid causes air-borne impurities, in particular dust and particulate matter to be retained in the fluid. Purified air is then allowed to pass into the room through an air outlet. The fluid circulates continuously from the reservoir to the plurality of tubes and back to the reservoir.
Preferably the air purifier apparatus is contained within a housing having air inlet and air outlet apertures. Each of the plurality of tubes is preferably non-linear and more preferably spiral in configuration to increase the length of time during which the air and fluid are in contact. The fluid reservoir is advantageously arranged in the base of the housing so fluid can return to the reservoir by gravity. The plurality of tubes terminates above and drains into the fluid reservoir. Air circulation is provided by pushing or pulling air from a space provided above the fluid in the reservoir, thereby drawing air in an inlet through the plurality of spiral tubes.
To increase the contact between the air and fluid, each tube making up the plurality of tubes may provided with a plurality of fluid delivering spray nozzles.
Further aspects of this invention will become apparent to those skilled in the art upon reading the following description.